Impact of Charging on Battery Life and Battery Degradation in Electric Vehicles

Introduction

Recalling the environmental conditions prevailing the whole world recently, there is a tendency to replace energy sources that are harmful to the environment dramatically and reduce their usage as possible. One of these initiatives are related with vehicles. Since they are one of the most useful objects in our daily life as it contributes to the least tasks of our day and they have sundry benefits and applications mainly to humans, it is necessary to focus on how they function, the type of energy they use and how they impact our surrounding environment. Due to the numerous advantages of the electrical energy, the concept of electric vehicle becomes very promising.

Furthermore, those electric vehicles will require recharging through an electrical energy supply that could be provided through charging stations; however, those EVs will act as an extra load to the main grid. Thus, a compromised solution has been obtained lately, which is developing micro grids. The micro grids act as a network of distributed generations (DGs), which are mostly based on extracting energy from renewable energy sources, in which those sources are found to be intermittent and suffers from high fluctuations. These key drawbacks of renewable sources may lead to low power quality and transmission limitations through micro grids and large power systems.

Hence, Energy Storage Systems (ESS) is considered as one of the solutions for overcoming the surging need of storing energy and changing the form of energy from one type to another. It is compulsory to review and select the optimum methods to save and store energy efficiently for later usage, in other words, picking the most efficient ESS based on the desired application and some other chief factors such as the storage capacity, the scalability, the cost, the transmission method, the amount of energy to be transmitted, the rate of transferring, the response of the system, the supply and demand of energy at some specific region, etc. The five main forms of categorizing ESS are dragged under the classes of mechanical, electrical, electro-chemical, chemical, thermal energy storage.

For illustration, in the scope of interest of EVs, batteries are found to be the main storage element based on the scalability of the required energy to be stored in EVs. Amongst several researches, Lithium-ion batteries are agreed on as the optimum and most promising battery, especially in the application of electric vehicles as they run for both relatively high cycling capability and elevated energy density; however, their main disadvantage is the high initial cost. So, it is necessary to take into consideration the main factors that affect the life of the battery.

Meanwhile, a case study for a proposed urban EV model was carried out to know the load that the batteries will be exposed to. The load identification was done based on some aspects such as providing a full description of the dynamical model, the forces exerted on the vehicle, inspecting its kinematics at certain cases; in addition to, assessing the dynamic responses of the system and obtaining the power losses of the EV at variable loads with respect to the velocity. Also, battery and motor sizing were carried out based on the battery and motor specifications provided by the manufacturer. All the previous points contribute to determining the total load on the micro grid.